• Microbiology and Biotechnology Letters
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• v.25 no.3
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• pp.277-285
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• 1997

Kluyveromyces marxianus var. marxianus isolated as an inulin-assimilating microorganism produces inulin fructotransferase (inulaseII) which catalyses the conversion of inulin into di-D-fructofuranose 1, 2' : 2, 3' dianhydrde (DFAIII). The DFA produced by the organism was isolated by using active carbon column, and identified as DFAIII by high performance liguid chromatography. The culture medium giving maximum inulaseII production was found to consist of 1% sucrose and 0.75% yeast nitrogen base (YNB). The inulasell production was induced by inulin or sucrose as a carbon source and increased by addition of YNB as a nitrogen source. Optimal initial pH of the culture medium, culture temperature and medium volume for the enzyme production were pH 4.7, 30$\circ$C and 140 ml, respectively. Under the optimal conditions described above, the enzyme activity in the culture supematant reached 4.2 units/ml after cultivation for 36 h. The DFAIII was accumulated at 13.25 mg/ml after 48 h of culture in the Jerusalem artichoke tuber medium.

• Applied Biological Chemistry
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• v.40 no.3
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• pp.184-188
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• 1997

A bacterial strain, producing extracellular inulin fructotransferase which converts inulin into di-D-fructofuranose 1,2':2,3' dianhydride(DFA III), was isolated from soil and presumed as Bacillus sp.. The highest production of the enzyme was obtained by using medium containing Jerusalem artichoke extract as carbon source, peptone as organic nitrogen source, and $NH_4H_2PO_4$, as inorganic source. Under optimum condition, the enzyme activity of the culture broth supernatant reached maximal 2.61 units/ml after cultivation for 45 hrs.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.36-40
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• 1993

A bacterial strain, producing extracellular inulin fructotransferase which converts inulin into di-D-fructofuranose dianhydride (DFA) was isolated from soil and presumed as Enterobacter sp. The DFA isolated on Bio-gel P2 column was identified as DFA III by high performance liquid chromatography and $^13C-nmr$ spectroscopy. The enzyme production was induced by inulin and markedly enhanced by the addition of corn steep liquor and $NH_4H_2P0_4$ for nitrogen source. Under optimum condition, the enzyme activity in the culture broth reached at maximum, 0.22 unit/ml after cultivation for 72 hour.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.102-108
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• 2006

The IscA gene, encoding a levansucrase of 424 amino acids (aa) residues, was cloned from the genomic DNA of Pseudomonas aurantiaca S-4380, and overexpressed in Escherichia coli. The recombinant levansucrase overexpressed in E. coli was then used to produce levan from sucrose. Levan crystals with 98% purity could be obtained from the reaction mixture with $62\%$ yield using an alcohol precipitation method. The molecular weight of the levan was $7\times10^5$ daltons. Methylation studies showed that the levan was branched: main linkage C-2,6; branched linkage C-2,1; and degree of branching $6\%$. Three bacterial levans from different strains were incubated with levan fructotransferase (LFTase) from Arthrobacter ureafaciens K2032, which produced $di-\beta-D-fructofuranose$ dianhydride IV (DFA IV); final conversion yields from the levans to DFA IV were $39\%$ in Zymomonas mobilis, $53\%$ in Serratia levanicum, and $59\%$ in P. aurantiaca S-4380 levansucrase. The levan from P. aurantiaca S-4380 levansucrase gave the highest conversion yield of levan to DFAIV so far reported.

• Preventive Nutrition and Food Science
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• v.13 no.1
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• pp.1-6
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• 2008

Di-D-fructose-2,6':6,2'-dianhydride (DFA-IV) is a disaccharide consisting of two fructose residues that are prepared from levan by levan fructotransferase. Levan is a homopolysaccharide composed of D-fructofuranosyl residues joined by $\beta$-(2,6) and $\beta$-(2,1) linkages. We compared the immunomodulatory effects of levan with DFA-IV. Tumoricidal activity, phagocytosis and nitric oxide (NO) production were examined in levan- and DFA-IV-treated RAW264.7 cells. The NO production, tumoricidal and phagocytic activities were significantly increased in both treated cells. The results indicate that levan has significantly greater effects on tumoricidal activity than DFA-IV at low concentrations (1 ${\mu}g/mL$) and its effect on NO production shows a similar pattern. These results suggest that tumoricidal activity induced by both samples is mediated by NO production.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.471-476
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• 1999

Inulin fructotransferase(depolymerizing)(EC 2.4.1.93)(inulaseII) which converts inulin into di-D-fructofuranose-1,2':2,3'-dianhydride (DFAIII) was purified from Arthrobacter ureafaciens KCTC 3387 using column chromatography on DEAE-Toyopearl 650M and gel filtration of Sephadex G-200. The enzyme was purified 7-fold with a yield of 11% from a culture supernatant. The purified enzyme gave a single band on polyacrylamide gel electrophoresis, and the molecular weight of the enzyme was estimated to be 45,000 by SDS-polyacrylamide gel electrophoresis. The optimum pH and temperature for the enzyme reaction were pH6.5~7.0 and $55{\circ}C$, respectively. The enzyme was stable within a pH range of 5.0 to 10.6 and up to $60^{\circ}C$. The Km of this enzyme for DFAIII production was 11.9mM. The enzyme was inactivated by $Hg^{2+}$ and after exhaustive digestion of inulin by this enzyme, 1-kestose and nystose were produced in addition of DFAIII.

• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.68-74
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• 1995

A bacterial strain A-6 producing the high level of an extracellular inulin fructotransfe rase(depolymerizing)(EC 2.4.1.93) which converts inulin into di-D-fructofuranose dianhydride III (DFAIII) was isolated from soil. The isolated strain could be classified as a species belonging to the genus Arthrobacter based on its morphological and physiological characteristics identified in this work. Production of the enzyme was induced by inulin, and the highest activity was detected in the slightly acidic medium supplemented with 2.5% inulin and 0.1% trypton as a sole carbon and a nitrogen source, respectively. Under the optimal conditions, the enzyme activity in the culture supernatant reached approximately 60 uints/ml after 96 hours of cultivation. The optimum pH and temperature for the crude enzyme preparation from Arthrobacter sp. A-6 were pH 5.0 and 60$\circ$C , respectively. The DFA produced by the action of the inulin fructotransferase was confirmed to be DFAIII by paper chromatography, HPLC and $^{13}$C-NMR spectroscopy.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.402-406
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• 1996

Inulin fructotransferase (depolymerizing) (EC 2.4.1.93) was purified 34-fold from the culture broth of Arthrobacter sp. A-6 by using a combination of ammonium sulfate fractionation, DEAE-Sepharose CL-6B chromatography and Sephacryl S-200 gel filtration. The purified enzyme converts inulin into di-D-fructofuranose dianhydride III(DFA III) and small quantities of fructo-oligosaccharides. The temperature and pH optima of the enzyme were $70^{\circ}C$ and 6.0, respectively. Molecular weight of the enzyme was determined to be 49 kDa by 12$%$ SDS-polyacrylamide gel electrophoresis, and 145 kDa by Sephacryl S-200gel filtration. This indicates that the functional inulin fructotransferase of Arthrobacter sp. A-6 has a homomeric trimer structure. The enzyme had an isoelectric point of pH 4.6. The N-terminal amino acid sequence of the purified enzyme subunit was Ala-Asp-Asn-Pro-Asp-Gly(\ulcorner)-Ser-Asn-Met(or Glu)-Tyr-Asp-Val.

• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.121-126
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• 1996

A bacterial strain LC-413, producing extracellular inulin fructotransferase which converts inulin into di-D-fructofuranose dianhydride(DFAIII) and amount of oilgosaccharides, was isolated from soil and pre-sumed as Flavobacteium sp. LC-413. The enzyme production was induced by inulin as carbon source and enhanced by the addition of 0.3% malt extract and 0.2% {TEX}$NaNO_{3}${/TEX} as nitrogen source. The enzyme activity in the culture supernatant reached at the maximum, 78.6units/ml, after 11 hours of cultivation in the medium composition of 1.5% inulin, 0.2% {TEX}$NaNO_{3}${/TEX}, 0.05% {TEX}$K_{2}${/TEX}{TEX}$HPO_{4}${/TEX}, 0.05% {TEX}$MgSO_{4}${/TEX}.7{TEX}$H_{2}${/TEX}O, 0.05% KCI, a trace amount of {TEX}$FeSO_{4}${/TEX}.7{TEX}$H_{2}${/TEX}O, and 0.3% malt ext. at 3$0^{\circ}C$. The oilgosaccharide produced by enzyme reaction from inulin was identified as DFA III by and {TEX}${13}^C${/TEX}-NMR spectrosocpy.

• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.37-43
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• 2007

A gene encoding inulin fructotransferase (di-D-fructofuranose 1,2': 2,3' dianhydride [DFA III]-producing IFTase, EC 4.2.2.18) from Bacillus sp. snu-7 was cloned. This gene was composed of a single, 1,353-bp open reading frame encoding a protein composed of a 40-amino acid signal peptide and a 410-amino acid mature protein. The deduced amino acid sequence was 98% identical to Arthrobacter globiformis C11-1 IFTase (DFA III-producing). The enzyme was successfully expressed in E. coli as a functionally active, His-tagged protein, and it was purified in a single step using immobilized metal affinity chromatography. The purified enzyme showed much higher specific activity (1,276 units/mg protein) than other DFA III-producing IFTases. The recombinant and native enzymes were optimally active in very similar pH and temperature conditions. With a 103-min half-life at $60^{\circ}C$, the recombinant enzyme was as stable as the native enzyme. Acidic residues and cysteines potentially involved in the catalytic mechanism are proposed based on an alignment with other IFTases and a DFA IIIase.